Cytomegalovirus disease in children with HIV can progress and cause serious morbidity, especially as their immune system becomes more compromised, leading to eye, GI, and pulmonary complications. Many children become infected with CMV early, yet the disease remains quiescent until the CD4 counts drop. This study will evaluate the pharmacokinetics, maximum tolerated dose, longterm safety and tolerance, and the effect on CMV virology or oral ganciclovir.